1. Field of the Invention
This invention relates to a mobile facsimile telecommunications system utilizing an automobile telephone system as a transmission path in general, and more particularly to an adaptor to be used between an automobile telephone device and a portable-type facsimile device having no dialing function in such a facsimile telecommunications system, and to a method of performing facsimile transmission by utilizing a polling transmission function of a facsimile device which is coupled, via an adaptor, to an automobile telephone device or a wireless telephone device with equivalent properties.
2. Description of the Prior Art
A mobile facsimile telecommunications system illustrated in FIG. 1 is well known as one prior technique for performing facsimile telecommunications utilizing an automobile telephone system as a transmission path.
In FIG. 1, the mobile facsimile telecommunications system comprises an automobile telephone device 1 including a radio transceiver 1a and a telephone set 1b, an adaptor 2 coupled to the telephone device 1, a facsimile device 3 connected to the adaptor 2, and an ordinary telephone set 5 connected to the facsimile device 3 through a cable 4 serving as an interface based on a two-wire loop dialing system (identical with an ordinary telephone subscriber line). In this arrangement, one end of the cable 4 is connected to telephone terminals of the facsimile device 3.
As illustrated in FIG. 3, the adaptor 2 comprises a MODEM 2a containing a network control unit (NCU) having an interface function for coupling the automobile telephone device 1 to the ordinary telephone subscriber line and a data processing unit for reading and discriminating serial data S1 of a given format transmitted from the automobile telephone device 1, a controller 2b including a G3-class communication control 2b-1, a main control 2b-2 constructed by a CPU, a ROM and a RAM and a RF communication control 2b-3, and for outputting a control signal S2 corresponding to the serial data S1, a V.27 ter. MODEM 2C in conformity with the Recommendations of the CCITT, and a central-office line part 2d constructed in an ordinary telephone subscriber signal format, adapted to be controlled by the control signals S2 from the controller 2b and provided with an interface function for the facsimile device 3.
In addition, the G3 communication control 2b-1 is provided with the same procedure as that of a standard G3 facsimile device in conformity with the CCITT Recommendations, and the MODEM 2a is provided with an error correction control function introduced by taking a wireless trunk line into account. The ordinary telephone set 5 in FIG. 1 is used because most of facsimile devices are not generally provided with dialing and polling transmission functions.
In operation, an operator first makes a telephone call to the other party and talks over the telephone by use of the telephone set 1b of the automobile telephone device 1, and then hangs up the phone after conversation. Next, the operator sets a manuscript into the facsimile device 3 and dials or phones again by use of the ordinary telephone set 5. At this juncture, the ordinary telephone set 5 and the adaptor 2 are placed under off-hook conditions due to a loop current flowing through a network control circuit (NCU) in the facsimile device 3.
The dial signals from the ordinary telephone set 5 are transmitted to the adaptor 2 through the NCU of the facsimile device 3. The adaptor 2 transforms the dial signals into a dial signal format suitable for an automobile telephone and sends them out to the radio transceiver 1a. When connected with a destined party, the adaptor 2 provides a response signal to the ordinary telephone set 5. Then, the operator confirms the presence of the response signal and will depress a start key on the facsimile device 3. Thus, the content of the manuscript is scanned and transmitted to the called party through the radio transceiver 1a.
As clearly understood from the foregoing, in the facsimile telecommunications system using such adaptor as illustrated in FIG. 3, it is required for the operator to manipulate two telephone sets. In fact, since the operator must enter into the facsimile communication by originating calls again after conversation, it will result in an increase of manipulation time and telephone charges. Besides, from the economical and special points of view, there were some problems in the use of an ordinary telephone set.
As another prior art for a facsimile telecommunications system in a moving body, T. Takahashi et al. "Error-Free FAX Communication Adaptor" Journal of Technology Transfer, Vol.12, No.11, pp.30-31, 1989 exhibits such an arrangement as indicated in FIG. 2.
In FIG. 2, a facsimile telecommunications system in a moving body comprises a wireless telephone device 1 mounted on a moving body such as automobiles or the like, for example. The wireless telephone device 1 includes a radio transceiver 1a, and a telephone set 1b provided with a key 1b-1 for transmitting an initiation signal S1 which is serial data of a given format. An adaptor 2 is coupled to the radio transceiver 1a and the telephone set 1b by way of cables A, A on one hand, and also coupled via cable B to a standard G3 facsimile device 3 recommended by CCITT on the other hand.
In the aforesaid arrangement, the cables A and B are interface cables. In particular, the cable A is a cable used for interfacing between the radio transceiver 1a and the telephone set 1b, and the cable B is an interface cable suitable for a two-wire loop dialing system. In addition, the facsimile device 3 includes a start key and a hook switch (both, not shown) and is provided with automatic response and polling transmission functions. The polling function is an alternative to contention networks wherein terminals are polled in sequence to see if they have anything to send. Polling prevents any one terminal from an overly long wait.
FIG. 4 is a detailed functional block diagram of the adaptor 2 in FIG. 2 and generally similar to that of FIG. 3, excepting for that the MODEM 2a in FIG. 3 is replaced by a cellular MODEM 2a' which includes an NCU (Network Control Unit) having an interface function for the wireless telephone device 1 and an ordinary telephone subscriber line, and is provided with modulation/demodulation and received-data error correction control functions. As seen from FIG. 4, the adaptor 2 comprises the cellular MODEM 2a' having various functions mentioned above, a controller 2b including a G3 communication control 2b-1 with a control function for the facsimile device 3, a main control 2b-2 and an RF communication control 2b-3 for controlling the cellular MODEM 2a', a V.27 ter. MODEM 2c with an interface function for the G3 communication control 2b-1 in conformity with the Recommendations of CCITT, and a central office line part 2d provided with an ordinary telephone subscriber signal format as well as interface function to the facsimile device 3 for outputting a call signal S2'.
In this arrangement, the call signal S2' has an on-off ratio of 201 PM and a make ratio of 33, and the frequency of 400 Hz is modulated with a signal of more than 15 Hz and less than 20 Hz.
The conventional facsimile telecommunications system constructed as shown in FIG. 2 is operated through the following steps:
(1) Set the manuscript to the facsimile device 3;
(2) Make a phone call to the receiving party using the telephone set 1b on the wireless telephone device 1;
(3) Depress the key 1b-1 on the telephone set 1b after having a conversation with the receiving party;
(4) Manipulate the hook switch or the start key on the facsimile device 3 after confirming the presence of the response signals from the adaptor 2.
As the result of the abovementioned procedures, the facsimile telecommunications system in the moving body indicated in FIG. 2 operates as follows.
In the step (3), when the key 1b-1 is depressed, the initiation signal S1 assigned to the key 1b-1 in advance is applied to the cellular MODEM 2a', and the operation thereof is conveyed to the controller 2b. Then, the controller 2b causes the central office line part 2d to generate the call signal S2' and to provide the facsimile device 3 with the call signal S2'. The facsimile device 3 will respond to it through the manipulation of the hook switch or the start key specified in the step (4). As the result, the facsimile device 3 is placed under an off-hook condition on a loop formed in between the adaptor 2 and itself via the cable B.
This condition corresponds to PHASE A (Call Setting) in the transmission control procedures based on the CCITT Recommendation T-30. Communication between the facsimile device 3 and the G3 communication control 2b-1 is successively continued according to the procedures of PHASE B (Premessage procedure), PHASE C (Message procedure), PHASE D (Postmessage procedure), and PHASE E (Call cancellation).
As described above, in order to send out the content of the desired manuscript using the facsimile telecommunications system illustrated in FIG. 2, the operator is required to depress the key 1b-1 provided on the telephone set 1b after conversation as pointed out in the step (3) and thereafter to manipulate the hook switch or the start key, thereby rendering the operationality in the case of the manuscript transmission rather complex or troublesome.
Besides, supposing that the telephone set 1b is located around the seat for a driver, whereas the facsimile device 3 is located at a back seat, for example, to which the driver himself may not reach from his position, the driver is required to move to the place where the facsimile device 3 is located within the car in order to manipulate the hook switch or the start key after depressing the key 1b-1 on the telephone set 1b. It will be clear that the operationality in this case becomes more complex or troublesome as compared to the previously mentioned case where the telephone set 1b and the facsimile device 3 are placed adjacent to each other.